The present invention relates to semiconductive or conductive polymers, a method of producing the polymers, and batteries using the polymers as active materials.
In recent years many studies on electronic materials have been conducted, and particularly functional polymeric materials using conjugated polymers attract attention because of their various feasibilities in the application. It is known that complex compounds formed by doping impurities on conjugated polymeric materials could exhibit electric conductivity comparable to dielectrics, semi-conductors or metals. Though the conduction mechanism is not clarified as yet, various materials expected to be as being functional materials are being studies.
Heretofore various polymeric materials such as polyparphenylene, polythiophene, polypyrrole, polyacetylene and derivatives thereof have been studied as reported in Japanese Laid-Open Patent Applications Nos. 61-4165 and 56-136469 and Journal of Polymer Science, Polymer Chemical Edition, Vol. 12. p.11-20. However, these polymeric materials do not have sufficient electroconductive characteristics for use in practice. No polyyne polymers having such electroconductive characteristics have been reported as yet.
Polyaromatic vinylene compounds represented by the following general formula (I) have been reported. Specifically, the syntheses and properties of polyphenylene vinylene and polthienylene vinylene are reported in Japanese Laid-Open Patent Application No. 61-4165 and Japanese Laid-Open Patent Application No. 61-148231, respectively. ##STR3## wherein Ar is a conjugated group.
It has been found that these aromatic vinylene compounds as well as other conjugated compounds are feasible for doping with impurities, and both n-type and p-type dopings are avaiable by the gas doping using a gas such as SO.sub.3, or by the electrolytic ion doping through an electrochemical method. The materials obtained by these methods are promising as new electronic materials with many applications.
In a method of producing these polymers, a sulfonium salt polymer having the following formula (II) is pyrolyzed to produce a polyaromatic vinylene compound, which requires a prolonged synthesizing process. ##STR4## where R represents an alkyl group, and Y represents an anion.
As a method of producing conjugated polymers such as polypyrrole, there is known an electrochemical polymerization method which utilizes an electrochemical method. In this method, an electric current is caused to flow through an solution of a monomer and an electrolyte, whereby a polymer is formed on an electrode. By this method, an electroconductive polymer can be obtained substantially by a single step, without addition of a secondary doping operation. When the electroconductive polymer is obtained in the form of a film, this method has the advantage that the thickness of the polymer film can be adjusted by controlling the applied electric current. The polymers studied by the electrolytic polymerization are such polymers that have been formed on the surface of an anode.
However, it is extremely difficult to synthesize polyaromatic vinylene compounds in which an aromatic unit such as phenylene, thienylene and furanylene, and a vinylene group are alternately bonded to each other, by the electrochemical polymerization method utilizing anodic oxidation. As a matter of fact, we are not aware of any reports concerning such synthesis.
It is reported that partial cathodic reduction was employed for polymerization. However, the polymers obtained by this reduction have a low electric conductivity and it is difficult to grow the polymers in the form of a thick film on the electrode.
Further, besides the above-mentioned polyene compounds, conjugated polyyne compounds such as polydiacetylene are synthesized as functional polymers mainly by solid phase polymerization and LB film formation technique (Lamgmuir-Brodgett's technique). However, there has been no report concerning the synthesis of a polymeric compound containing as the main chain a polyyne in which an aromatic unit such as phenylene group, and --C.tbd.C-- group are alternately bonded to each other.
Furthermore, there has been reported no organic battery using a polyyne compound as the active material thereof.